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Table of Content

    25 December 2019, Volume 41 Issue 12

    Study on the coal consumption and pollutant discharge characteristics of coalfired units participating in deep peakregulating operation in Anhui Province

    MA Dawei1,WANG Zhengfeng2,HE Jun1,HUANG Qishun1,CHEN Jian1,ZHANG Benyao1,WU Xu2,CONG Xingliang1
    2019, 41(12):  1-7. 
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    Because of the power structure of installed units and status quo of clean energy in Anhui Province,coalfired units participate in deep peakregulating operation regularly.Taking 94 coalfired units as study objects, pollutant mass concentration in flue gas, variation trend of coal consumption for power supply and peak shaving compensation capacity are analyzed. The results show that the levels of pollutant emission and  coal consumption for power supply of coalfired units in Anhui Province rank on the top of China.During deep peakregulating operations , the NOx mass concentration in flue gas may exceed standard due to the suspension of ammonia injection which results from the flue gas temperature at the denitrified inlet being lower than the minimum operating temperature of the catalyst.The problem can be solved by choosing lowtemperature SCR catalyst, setting flue gas bypass for the economizer, separating the flue duct and updating the economizer in stages.The coal consumption for power supply changing with the load rate is a convex curve, and it increases more rapidly as the the load rate decreases. It indicates that the operating economy of the unit participating in the deep peakregulating operation is significantly reduced. After calculating the added cost of peakshaving, taking classified quotation, and setting energysaving and emissionreduction coefficient formulas, a peakshaving auxiliary service market is established to compensate the power generation enterprises that actively participate in deep peakregulating operation.

    Mechanism and technology development of magnetic adsorbent for mercury removal

    SHANG Yongqiang1,ZHAO Yongchun2
    2019, 41(12):  8-15. 
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    Aiming at the shortcomings of the existing collaborative mercury removal technology and activated carbon spray mercury removal technology, a new method of preparing renewable magnetic mercury removal adsorbent using ferrospheres in fly ash was proposed.The modified ferrospheres with active component were prepared by dippingthermal decomposition method.The mercury removal performance of the modified ferrospheres in flue gas with complex components was investigated in fixed bed adsorption experiments and the mechanism of mercury removal was explored. After multiple recycling and regeneration mercury removal experiments,the results show that the modified ferrospheres maintain high mercury removal efficiency in complex lowchlorine flue gasand it is of good acid resistance.The mercury removal performance of ferrospheres comes from the heterogeneous oxidation reaction of lattice oxygen or adsorbed oxygen, active chlorine and Hg0.The modified ferrospheres can be regenerated by heating in air stream containing O2 and HCl, and mercury will be desorbed from the adsorbent surface at high temperature.The modified ferrospheres adsorbent has good regeneration performance and maintains a strong mercury removal capacity after multiple recycling and regeneration.

    Research and application of new flue gas ultralow emission technology

    ZHANG Jiantong,WANG Dianchang,WANG Jilun
    2019, 41(12):  16-19. 
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    In order to meet increasingly stringent environmental protection requirements, reduce investment in engineering equipment and maintenance costs, taking the developing large units and suppressing small ones2×660MW ultrasupercritical condensing heating units in Huadian International Shiliquan Power Plant as an example, the application of gas flue ultralow emission technology was studied. The units removed the wet separator that was of great waste water production, maintenance and power consumption, and adopted a fullload technical solution which was selective catalytic reduction (SCR) denitration+lowlow temperature electrostatic precipitator+ highefficiency desulfurization collaborative dust removal FGDPlus+media  gasgas heater(MGGH). After more than 2year operation, the flue gas emission has always met the ultralow emission and strict national environmental protection requirements, which can provide a reference for the construction and ultralow emission retrofit of the sametype unit.

    Application of flow field simulation in SCR honeycomb denitrification catalyst mold design

    QIN Yiming,HAN Tongjiang,WANG Guanyu,WANG Jianguo,CHEN Hua
    2019, 41(12):  20-24. 
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    Selective catalytic reduction(SCR)honeycomb denitrification catalyst is subject to many factors while extrusion. In order to explore the key parameters affecting the extrusion of catalyst mold, flow field simulation during the extrusion process of catalyst is made by ANSYS Fluent. The influence of main parameters such as mold boss, feed hole and slit width are analyzed, which provide an idea for the design of catalyst extrusion mold.

    Application and development of zeroemission treatment technology for desulphurization waste water from coalfired power plants

    ZHANG Shanshan,WANG Renlei,JIN Yinjia,TANG Guorui
    2019, 41(12):  25-30. 
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    Limestonegypsum wet desulfurization technology was widely used in the flue gas desulfurization process of coalfired power plants, but the desulfurization waste water produced in the process is of high salinity, heavy metal, complex composition, corrosivity and is vulnerable to scale. It is one of the most difficulttreated waste water from thermal power plants.Resourcescharacteristicstraditional treatments and reusing methods of  desulfurization waste water were described.The main technical route and application status of desulfurization waste water zeroemission were introduced, and so did its research direction in the future. It was considered that an optimum desulfurization waste water zeroemission technical route for a power plant should be designed based on its water quality and quantity.Bypass flue duct gas evaporation technology is applied well and of economic advantages, which provides a direction for desulfurization waste water recycling and lowcost treatment.

    Research and progress in the technique of heavy metal ions removal from waste water

    LIU Yangzhi1,LIU Peng2
    2019, 41(12):  31-36. 
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    With the rapid development of industrial technology, various pollutants are discharged into the environment. Among them, heavy metals can hardly be degraded due to their richness, which causes great harm to the environment and human body. The relevant domestic and international research methods for removing heavy metal ions from waste water  are described, and the corresponding classical theoretical results  based on various removal methods are proposed. By describing the advantages and disadvantages of various methods, a new type of water treatment adsorption material with great development prospects is introduced, and its related progress in  heavy metal ion removal is summarized.

    Technical schemes for waste heat deep utilization in gas distributed energy stations

    DIAO Peibin1,XU Jingjing1,2,YU Li1,2,JIANG Ting1,2,LIU Guangyu2,HU Yongfeng2
    2019, 41(12):  37-40. 
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    To increase the utilization rate of gas distributed energy stations,taking the design of a distributed energy project as an example, analysis was made from equipment selection, operation mode, investment and operation economy, and a waste heat deep utilization scheme was proposed. The technical scheme was introduced from the technological process  and operation modes under different load conditions in detail, and its economy was compared with conventional technical schemes.If there is sufficient and stable heating demand, distributed energy project can be economic within a reasonable waste heat deep utilization scheme.

    XU Yaowei1,ZHU Chen1,ZHANG Wenke2
    2019, 41(12):  46-49. 
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    Optimization design for electrical control systems in gas distributed energy stations

    CHEN Jing1,ZHANG Xi2,DU Juhu2,LIU Jing2
    2019, 41(12):  50-53. 
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    The isolated function and incomplete monitoring scope of current electrical control systems in gas distributed energy stations have brought great inconvenience to operators. In order to solve the problems above, improve integration level of electrical control system, and facilitate the unified control and management for operators, an integrated design of a new electrical control system for gas distributed energy station is proposed. The system is composed of power distribution and sales control subsystem, power generation control subsystem, auxiliary power control subsystem, stepup substation control subsystem and telecontrol communication control subsystem. These subsystems are all connected to double Ethernet and clock synchronization bus through communication management unit. The system realizes the integration of  power generation and sales, which makes the operation of distributed energy station more flexible, efficient and economic.

    Study on the distribution and optimization control of SCR denitration system flue gas flow field

    LIN Qing
    2019, 41(12):  58-62. 
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    The optimization for flue gas field of international and domestic  SCR denitration systems is limited to the optimizing of deflector design through numerical and physical simulations, and the results are unstable. Based on the uniformity detection for flue gas field at SCR denitration inlet during operation, and the internal inspection for denitration flue duct during shutdown, the design and numerical simulation for ammoniasmoke mixed flow spoiler at denitration inlet were executed, and the optimum flow spoiler was selected and installed. The ammonia injecting adjustment was made after the project, and the flow field of SCR denitration system was optimized.The project reduced the ammonia consumption for denitration and the production of NH4HSO4, also alleviate the blockage of air preheaters and the wear and blockage of the denitration catalyst.At the same time, it provides reference and technical support for other similar units in solving the problems above.

    Development and application of coal quality prediction system for trains

    CHEN Zonghui,ZHANG Linqu,GOU Jin
    2019, 41(12):  63-67. 
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    The traditional coal quality prediction for trains is mainly manual, and its labor intensity and the deviation of coal quality prediction is high. Based on coal management experience of a power plant, the relationship between coal quality and loading volume was found out through mathematical model. The prediction of coal quality was finally realized based on loading height, which provided basis for coal stacking and blending burning. It can be widely used in thermal power plants for rail transportation and initial judgment for coal quality.

    Evaluation method on new energy intensive management for integrated energy services

    WU Zhijun
    2019, 41(12):  68-71. 
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    With the advent of “grid parity era” of new energy, the business pressure of new energy enterprises have become more prominent.Traditional power generation enterprises are of redundant personnel,long chains,high costs and low efficiency,which severely restrict the development of integrated energy services of new energy enterprises.Taking a new energy company in Northwest China as the research object,adopting a regional intensive management model for new energy to replace the traditional management model ,intensive management transformations for administration and production of power generation enterprises are carried out.The production and operation,quality and safety,finance and personnel management functions of new energy power stations affiliated to one regional company are all integrated in the regional company. Power generation stations are managed by production teams,and the management structures are streamlined,and configurations are standardized by means of digital platforms such as remote centralized control system,equipment cloud maintenance system and so on.The evaluation method on new energy intensive management for integrated energy services are studied and the results show that the intensive management model reduces management costs of power generation enterprises, improves the work efficiency and production management.The labor productivity of the company has become industryleading.

    Exploration of permanent magnet speed regulation energysaving technology and its application on 6kV motors

    WANG Xiaolin,KE Niankai
    2019, 41(12):  72-77. 
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    According to the National Energy Conservation and Emission Reduction Work inthe 13th Fiveyear Plan, energy conservation of motors is an important part of energy conservation and emission reduction. There are large number of highpower motors in auxiliary systems of thermal power units, and most of them operate in power frequency mode, with high energy consumption in throttle governing and low efficiency.To reduce the energy waste of motors, it is necessary to optimize the energysaving technology for the system. Taking a power plant as an engineering case, the energy saving effect of permanent magnet speed regulation energysaving technology on 6kV motors is proven by experimental data.The permanent magnet speed regulation mode has wide speed regulation range, can realize process control and is of high reliability and long service life.It provides experience for exploring energysaving technology for motors in the future.

    Impact and preventive measures for total loss of oxidizing air on main desulfurization tower of a coalfired power plant

    YANG Junqiang,YANG Xiaofei
    2019, 41(12):  78-80. 
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    Limestonegypsum wet flue gas desulfurization process is taken by 2×330MW subcritical coalfired units in a heatsupply power plant. After ultraclean transformation taking singletower doublecirculation technology, the absorption tower sets up two oxidation fans(one for normal operation and one for backup). During the normal operation of the unit, the oxidizing air is totally lost, which causes the increase of slurry pH in the absorption tower and the increase of SO2 mass concentration at the unit outlet. The hazards of total loss of oxidizing air in the absorption tower are analyzed, and preventive measures during operation are proposed, to ensure the safe, reliable and economical operation of the desulfurization system.